Currently, touch display devices have been widely used on many occasions and fields as input devices substituting for or supplementing commonly used keyboards and mouse devices. With the production of a new generation of touch display devices supportive of multi-point touch interaction, great changes have taken place in applications of touch display devices. Touch display devices are now able to provide users with more interactions in more natural ways.
For existing touch display devices, especially those large-sized (e.g., 55-110 inches) ones, only after a user has finished the touch operation, the system of the touch display device is able to recognize a gesture input based on a received trajectory of the touch input and then execute a function corresponding to the gesture input. Due to the large size of these touch display devices, when performing a touch operation, the user has to move widely throughout the touch display device, i.e., move his or her finger(s) or a touch input device (e.g., a stylus) widely across the screen, so as to activate a desired function. This results in the user's fatigue and a disagreeable user experience.